Specific Pathogen Free (SPF) is a general term used to indicate that certain pathogens (disease causing microbes) have been excluded from an animal or a colony of animals. SPF facilities are designed to maintain rodents (both normal and transgenic) in an environment that is free of certain infectious organisms that are pathogenic and capable of interfering with research objectives. Like all animals, rodents are susceptible to a variety of viruses, bacteria and parasites. Some of these agents are capable of inducing disease outright, while others may significantly alter host responses to experimental conditions without causing overt signs of disease. Personnel working in these facilities must adhere to strict guidelines and standard operating procedures to avoid introducing pathogens into the facility.
If a pathogen is detected, the entire animal housing room is placed under quarantine until the infected rodents are identified and removed, and successive rounds of sentinel testing demonstrate that the pathogen is no longer present. Length of quarantine depends, in part, on the type of pathogen, and how well SPF procedures were followed prior to quarantine. Depending on how widespread the pathogen is, the cost of an “outbreak” detection may exceed tens of thousands of dollars.
Specific steps must be followed closely in order to avoid contamination to the SPF environment and to research animals. Personnel may be required to put on shoe covers as they step across the threshold of the doorway into the room. In some SPF facilities (termed Barrier SPF), one must take a shower first. Once in the room, a hair bonnet, gloves and lab coat are required. To work in a dedicated hood within the room, personnel must typically put on a set of sleeves to cover their forearms and a second pair of gloves so that the gloves overlap the cuff of the sleeves.
During the transfer of an animal cage to a dedicated hood for procedural testing and/or animal husbandry (e.g., changing the bedding, water or food), care must be taken to ensure that the filter-top (i.e., micro-isolator lid) stays securely in place as it protects the inside cage environment from any airborne pathogens that could infect the animals. All items (i.e., cages, supply boxes, one's gloved hands) that go into the hood must be sprayed with disinfectant prior to their entry per standard SPF operating procedures. Once the item is sprayed with disinfectant, it may enter the hood and be placed on the work surface.
The current procedure used for disinfecting an animal cage with animals, e.g. rodents present, (and other items) is done manually by “hard-spraying” the cage with disinfectant employing a typical spray bottle, which is the standard practice worldwide. The end user holds, and carefully rotates a cage in one hand while spraying disinfectant on the external four sides, as well as the bottom, with the other “free” hand. Extreme caution must be used when rotating the cage as to avoid dropping the cage on the floor, which could potentially injure and/or kill the animal(s) inside. Note, a standard mouse cage measures 11½″L×7½″W×5″H and can house up to 1-5 animals or more (litters) while a standard rat cage measures 19″L×10″W×8″H and can house up to 3 animals or more (litters). The size of these cages alone makes them extremely difficult to handle with one hand. Once the cage has been sprayed it's extremely slippery and even more difficult to control.
The amount of time required to disinfect a single cage using the current “spray bottle method” can take up to 15 seconds or more. Rodent cages must be changed on a weekly basis by dedicated animal care staff and may also be handled on a daily basis, often multiple times, by the research investigative groups that need to perform experimental procedures. In 2006, the University of Washington (UW) alone had an annual rodent use of 193,412 (180,087 mice and 13,325 rats) with an average daily inventory of 102,718 (100,174 mice and 2,544 rats). The number of cages required to house these animals on any given day is ˜40,457. The time required to ensure proper disinfecting of cages during bedding change by dedicated animal care staff alone is equivalent to ˜168.5 hrs/wk or 4.2 full time employees (FTEs) (˜40,457 cages×15 seconds/cage). This is a conservative estimate and does not include the time that research investigators must spend spraying down their cages prior to beginning any work in the hood. The present invention will substantially reduce the amount of time it takes to disinfect a single cage employing the “spray bottle method” as the time (duration; set to 1 second (or less) vs. 15 seconds) and volume (amount) of spray can be metered/controlled. This can be translated to a significant reduction in labor cost (˜10 hrs/wk (0.25 FTE's) vs. ˜168.5 hrs/wk (4.2 FTEs)).
The standard “spray bottle method” currently used globally, is time consuming, inefficient, wastes disinfectant, and increases the risk of error by laboratory personnel which may lead to possible pathogen contamination to valuable animals because one cannot ensure 100% coverage. Additionally, the spray bottle method may increase ergonomic injury due to handling slippery cages with one hand and having to repeatedly pull the trigger of the spray bottle with the other hand. Therefore, a need exists in the art to substantially reduce the amount of time required to disinfect animal cages entering a sterile hood, e.g., dedicated work space, decrease the risk of human error and increase end user handling control thereby reducing the potential for pathogen contamination and endangerment of animals and provide 100% “proof of disinfection”.